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| Keywords: Poulsen arc converter circuit.png Poulsen arc converter an early radio transmitter invented by Valdamar Poulsen in 1903 from his 1904 paper It was one of the first continuous wave radio transmitters capable of transmitting sound AM and was used in many of the first radio stations until the early 1920s when it was replaced by vacuum tube transmitters It consists of a continuous electric arc across a spark gap SG supplied with a DC voltage V<sub>DC</sub> of about 500 volts A resonant circuit consisting of a capacitor C and an inductor L is connected across it The negative resistance of the arc cancels the inherent positive resistance of the tuned circuit exciting sinusoidal oscillations in the tuned circuit The arc is inside a chamber of hydrogen gas which allows higher frequency oscillations The oscillations are encouraged by a magnetic blowout an electromagnet M that generates a magnetic field at right angles across the arc At the peaks of the current the magnetic field exerts a a transverse force on the moving ions blowing them out of the arc cooling it causing the current to decrease quickly The radio frequency choke RFC prevents the oscillation current from passing through the power supply Alterations to image added labels red to the parts 1904 Retrieved May 28 2015 from https //books google com/books id NI8LAQAAIAAJ pg PA967 V Poulsen System for producing continuous electric oscillations in Transactions of the International Electrical Congress St Louis 1904 Vol 2 Section C Electrochemistry J B Lyon Co 1905 p 967 fig 3 on Google Books Valdamar Poulsen Valdamar Poulsen died in 1942 other versions PD-old-70-1923 Uploaded with UploadWizard Poulsen arc transmitters | ||||
